Is sneaker innovation changing how we move?

Sneakers are a relatively recent innovation that owe their existence, according to Elizabeth Semmelhack, senior curator at the Bata Shoe Museum, to the rubber tree. 

“Sneakers right from the beginning were part of the technological revolution that was happening in the 19th century. They were absolutely one of the newest forms of footwear ever created,” Semmelhack says. “The sneaker was reliant on rubber.”

Rubber has been around for centuries, but in its early uses, exported from South America to Europe, it would melt in summer and freeze in winter. It wasn’t until the 19th century that scientists figured out how to make stable rubber by boiling it and adding sulfur. 

“Once that occurred it was 1839,” Semmelhack says. “The sneaker was then possible.”

Sneakers went through many changes until the 1970s when people began experimenting with the rubber soles of shoes, mashing them with rolling pins, and, in the case of Nike co-founder Bill Bowerman, pouring them into his wife’s waffle maker. 

“This is the inspiration for the waffle trainer, one of Nike's most iconic shoes that came out in 1974,” Semmelhack says. “He coupled that with a nylon upper in bright eye-catching colors and he was able to make not only an exceptionally lightweight running shoe, he also was able to make one that caught on in fashion as well.”

Ever since Bowerman took over his wife’s waffle maker, sneaker technology has been growing in leaps and (pun-intended) bounds.

“Given that sneakers are related to technological advances and have been since the first sneaker ever emerged, it is always a place that is seen as acceptable for the latest and greatest,” Semmelhack says. 

“The evolution of sneakers is probably the most advanced of almost any product next to probably a car,” says D’Wayne Edwards, former footwear design director at Nike’s Jordan Brand.

Designers have sought to soup up their sneakers with electronics, synthetic rubbers, polyvinyl chloride, titanium and all different kinds of chemical compounds. 

“We're taking things from vehicles, from spaceships, from other manmade things,” says Edwards, who went on to found Pensole Footwear Design Academy after working on designing Air Jordans. 

Edwards and other shoe designers are always looking to have their shoes improve athletes' performance, making them lighter, stronger, faster. “What we're ultimately trying to do is make the shoe an extension of the human foot to the point where it moves and functions at the same speed that your foot naturally moves.” 

Shoes have come such a long way that scientists say they are actually capable of changing the ways humans’ bodies function and perform.

“I think that shoes can provide a lot of advantages,” says Roger Kram, associate professor of integrative physiology at University of Colorado, Boulder. “I'm an expert in running shoes, and spiked shoes give you much better traction than running barefoot.”

In addition to adding traction, wearing shoes also changes the way humans move their limbs. 

“About 90 percent of people who run in shoes will land on their heel, and about 90 percent of people when they take their shoes off will run on the ball of their foot. That's a pretty dramatic difference if you think about it,” Kram says.

Shoe designers and scientists say there is still room for sneaker designers to innovate. Some talk about making the shoes more activity-specific, others about making the shoes lighter. 

Kram predicts shoes will eventually become more tailored to people’s individual bone structures. “One of the big things there is to integrate the prosthesis into the bone, into the skeleton itself. And I can imagine at least integrating the shoe into the foot more biologically.”

This article is based on an interview that aired on PRI's Science Friday with Ira Flatow